Implantable medical devices typically include a wireless telemetry link that permits communication between the implanted medical device and an external programmer or patient monitoring device. The wireless telemetry link may permit the transmission of commands from a programmer or patient monitoring device to the implantable medical device, e.g., to program new features or functionality into the implantable medical device. Also, the wireless telemetry link may permit the programmer or monitoring device to interrogate the implantable medical device to obtain stored operational information and sensed physiological parameters.
A transceiver and antenna typically are located within a housing associated with the implantable medical device. Conventional programmers and patient monitoring devices incorporate a transceiver head that is placed in close proximity to the implantable medical device for programming and interrogation. The transceiver head may be coupled to the programmer or monitoring device via a cord. More recently, telemetry systems for implantable medical devices have eliminated the need for a transceiver head in the programmer or monitoring device. Instead, various wireless communication techniques have been implemented to permit increased transmission distances between the implantable medical device and the programmer or patient monitoring device.
Improved wireless communication techniques may permit the implantable medical device to be located several meters from the programmer or monitoring device, providing the patient with increased mobility during programming and interrogation. In some cases, a patient monitoring device may be placed within the home of a patient, and configured to monitor the implantable medical device by wireless telemetry during the course of the patient's daily routine. In addition, some patient monitors may take the form of portable devices that can be carried with the patient, e.g., much like a personal digital assistant (PDA) or cell phone.